net/sched/sch_cake.c

373 static void cobalt_newton_step(struct cobalt_vars *vars)
378 	invsqrt = vars->rec_inv_sqrt;
380 	val = (3LL << 32) - ((u64)vars->count * invsqrt2);
385 	vars->rec_inv_sqrt = val;
388 static void cobalt_invsqrt(struct cobalt_vars *vars)
390 	if (vars->count < REC_INV_SQRT_CACHE)
391 		vars->rec_inv_sqrt = cobalt_rec_inv_sqrt_cache[vars->count];
393 		cobalt_newton_step(vars);
424 static void cobalt_vars_init(struct cobalt_vars *vars)
426 	memset(vars, 0, sizeof(*vars));
449 static bool cobalt_queue_full(struct cobalt_vars *vars,
455 	if (ktime_to_ns(ktime_sub(now, vars->blue_timer)) > p->target) {
456 		up = !vars->p_drop;
457 		vars->p_drop += p->p_inc;
458 		if (vars->p_drop < p->p_inc)
459 			vars->p_drop = ~0;
460 		vars->blue_timer = now;
462 	vars->dropping = true;
463 	vars->drop_next = now;
464 	if (!vars->count)
465 		vars->count = 1;
473 static bool cobalt_queue_empty(struct cobalt_vars *vars,
479 	if (vars->p_drop &&
480 	    ktime_to_ns(ktime_sub(now, vars->blue_timer)) > p->target) {
481 		if (vars->p_drop < p->p_dec)
482 			vars->p_drop = 0;
484 			vars->p_drop -= p->p_dec;
485 		vars->blue_timer = now;
486 		down = !vars->p_drop;
488 	vars->dropping = false;
490 	if (vars->count && ktime_to_ns(ktime_sub(now, vars->drop_next)) >= 0) {
491 		vars->count--;
492 		cobalt_invsqrt(vars);
493 		vars->drop_next = cobalt_control(vars->drop_next,
495 						 vars->rec_inv_sqrt);
504 static bool cobalt_should_drop(struct cobalt_vars *vars,
530 	schedule = ktime_sub(now, vars->drop_next);
534 	next_due = vars->count && ktime_to_ns(schedule) >= 0;
536 	vars->ecn_marked = false;
539 		if (!vars->dropping) {
540 			vars->dropping = true;
541 			vars->drop_next = cobalt_control(now,
543 							 vars->rec_inv_sqrt);
545 		if (!vars->count)
546 			vars->count = 1;
547 	} else if (vars->dropping) {
548 		vars->dropping = false;
551 	if (next_due && vars->dropping) {
553 		drop = !(vars->ecn_marked = INET_ECN_set_ce(skb));
555 		vars->count++;
556 		if (!vars->count)
557 			vars->count--;
558 		cobalt_invsqrt(vars);
559 		vars->drop_next = cobalt_control(vars->drop_next,
561 						 vars->rec_inv_sqrt);
562 		schedule = ktime_sub(now, vars->drop_next);
565 			vars->count--;
566 			cobalt_invsqrt(vars);
567 			vars->drop_next = cobalt_control(vars->drop_next,
569 							 vars->rec_inv_sqrt);
570 			schedule = ktime_sub(now, vars->drop_next);
571 			next_due = vars->count && ktime_to_ns(schedule) >= 0;
576 	if (vars->p_drop)
577 		drop |= (get_random_u32() < vars->p_drop);
580 	if (!vars->count)
581 		vars->drop_next = ktime_add_ns(now, p->interval);
583 		vars->drop_next = now;